Currently, botanical or herb agricultural products are dried and cured in a conventional manner, with temperature and humidity control, over a period of weeks, months, or even years for some teas. This process is prone to product loss and loss of product value through mold, mildew, loss of terpenes (essential oils), and browning of the flower and darkening of the extract, among other price point indicators. Additionally water interferes with supercritical CO2 extractions as it is a common modifier in these extractions and introduces a process variable. For these reasons the botanical products are often thoroughly dried, causing additional loss of volatile essential oils and darkening of the extract due to oxidation of compounds.
Large investments are required to properly equip and operate a conventional dry room. High air flow requirements, and associated HVAC costs, are important to prevent mold and mildew. And while the ventilation removes ethylene and its byproducts, the loss of volatile compounds is accelerated. Traditionally, significant space must be dedicated to a conventional drying process—often taking 3 weeks or more, with the risk of product degradation being a natural outcome.
Freeze drying can be accomplished in hours, while preserving the essential oil profile of the plant and limiting oxidation. Alcohol extractions can pull water, thereby changing the solubility of the system and discriminating against lipid soluble compounds like essential oils. Furthermore, water sensitive extractions like supercritical CO2 and alcohol will be able to use thoroughly dried material that has retained more of the organoleptic and quality characteristics customer's desire.
Freeze drying of botanicals can reduce the time and risk involved in traditional drying methods, preserve organoleptic indicators, and remove variable water content that may interfere with extractor operation (supercritical CO2 in particular). For these reasons multiple moisture endpoints are desirable with botanicals depending on the end use, where traditional freeze drying targets the 1% to 3% moisture required for extended shelf life of foodstuffs.
However, in the drying of botanicals, curing is also commonly combined into one process. Freeze drying only addresses the drying of the botanicals, and not the chemical and biological changes taking place during curing. Historically, botanicals have been dried initially, then cured or cured as part of the drying process. In some cases it can be advantageous to dry the botanicals to a higher moisture content rapidly with the freeze drier, and then finish at different conditions under various gases to optimize the curing process while removing the risk and time from the preliminary drying step.
As such, there is a need for a new and improved system and method of addressing these deficiencies and problems presented with conventional drying and curing of botanicals.